Fermenting, fermentation and associated issues - as part of the Cider makers FAQ
Should sulphite be used in real cidermaking?
Some excellent cider can be made without sulphiting at all or adding yeast. That's the 100% natural fermentation method - well done if you can pull it off.
Adding sulphite is advocated by those who view it as an insurance policy to prevent various faults from developing due to unwanted microbial activity, or to ensure that a specific cultivated yeast takes over from any wild yeasts present. People who object that sulphite is not traditional tend to forget that cider and wine barrels were traditionally sterilised by burning 'sulphur candles' inside them. This left a residue of sulphite inside the cask which could then work its magic on the next fermentation in that barrel. Nowadays the use of controlled amounts of sulphite can be done much more accurately than the haphazard use of sulphur candles.
What are Campden Tablets, Sulphite and SO2?
SO2 (Sulphur Dioxide) is a noxious gas and very dangerous to human beings in high concentrations. As such it is exceedingly useful as a killer of bacterial, fungal and unwanted yeast contaminants. It is most commonly used by cider makers (as well as brewers and wine makers) as a sterilising agent in juices, typically in the 50 - 150 parts per million range. For sterilising barrels, higher concentrations in the percentage range are used. It is not a cleaning agent however, which is a common misconception.
Campden tablets are a convenient form of obtaining, handling and measuring SO2, as they are a compressed tablet form of Sodium Metabisulphite, a compound that generates and releases SO2 when in an acid solution. The higher the acidity in the solution (i.e. the lower the pH), the more SO2 is generated. Sodium Metabisulphite is available as a powder from many outlets (supermarkets, chemists, home-brew shops, etc.) and is the best form to use when making up an SO2 solution. Sulphite (or Sulfite) is simply a general term for SO2 and is now commonly seen on product labels, ie. "Contains Sulphites" as required by EU Allergy Labelling regulations.
To clean items of equipment, basic hot water and detergents are still excellent, followed by a rinse or wipe over with SO2 solution. Another excellent cleaner and steriliser combined are the Chlorine-based products such as 'Milton', 'Brewclens', 'Chempro-SPD', etc.
1) SO2 needs very careful handling; try not to inhale the fumes and ensure the room / area is well ventilated. Asthmatics, etc. should take particular care.
2) Follow any instructions carefully, particularly when mixing Campden tablets / Sodium Metabisulphate with any compound or liquid that contains acid, ie. lemon juice or malic acid.
3) You must rinse very carefully with clean water after using any of the Chlorine-based cleaner-steriliser products. However, small amounts of SO2 solution will not unduly affect any cider or juice so thorough rinsing is not so critical here.
What is the best way to use Campden tablets?
For most basic uses, simply crush the required number of tablets between two metal spoons or for larger numbers, use a pestle and mortar. Stir the resultant powder into the juice / cider / etc. These tablets can take a long time to dissolve, so crushing them makes their effect much more immediate. The crushed powder can also be easier to 'measure' for example, if you only required half or three-quarters of one tablet...
(An even better way of measuring and dosing with Sulphite is to make up a 'stock solution'. For full details of this, visit Andrew Lea's website.)
In the pH range 2.5 - 3.0 (very acid juice) you don't need to add any Campden tablets at all
In the pH range 3.0 - 3.3 (acid juice) you typically need 50 ppm SO2 or 1 Campden Tablet per gallon of juice
In the pH range 3.3 - 3.5 (not very acid juice) you typically need 100 ppm SO2 or 2 Campden Tablets per gallon of juice
In the pH range 3.5 - 3.8 (low acid juice) you typically need 150 ppm SO2 or 3 Campden Tablets per gallon of juice
The SO2 / Campden Tablets are added to the juice, allowed to stand overnight, and then a yeast culture is added on the following day. Fermentation should begin within a week or so.
If you want to use a 'semi-natural' fermentation (i.e. killing off the most undesirable wild yeasts, moulds and bacteria but without adding a cultured yeast) you should use say half the amounts of SO2 given above, and be prepared to wait up to a fortnight for the natural fermentation to begin.
Just about any yeast suitable for fermentation of fruit based musts can be used for cider. Yeasts specifically not recommended are those for Beer or Bread making, and it would probably be best to avoid yeasts selected for high alcohol tolerance or 'turbo yeasts' since an ideal fermentation for cider is slow and steady. If you have added SO2 to the juice, remember to leave 12-24 hours before pitching in a cultured yeast.
For a traditional style English cider, use an ale-type yeast. For a Normandy style cider use a wine yeast. Kitzinger, Hock, and Champagne yeasts all give good results. The finished product is paler than English cider and tastes closer to apple wine than does English cider.Source
Vigo sell a yeast ideal for cider, Uvaferm BC (S Bayanus).
See also under Cidermaking_Equipment#Yeast
What is malo-lactic fermentation? Is it necessary
How can I encourage malo-lactic fermentation?
Q I have heard that you can buy malolactic culture to ensure the onset of such fermentation. Where it can be purchased?
A You can buy cheaper (different brand than Vigo) and for smaller quantities from Brouwland in Belgium. See http://www.brouwland.com and enter <Malocid> in the search box.
What is keeving? Why do it?
Where can I obtain Pectin Methyl Esterase, as I would like to try a keeve?